[V2,2/8] mdev: class id support

Submitted by Jason Wang on Sept. 24, 2019, 1:53 p.m.

Details

Message ID 20190924135332.14160-3-jasowang@redhat.com
State New
Headers show
Series "mdev based hardware virtio offloading support" ( rev: 3 ) in Intel GVT devel

Not browsing as part of any series.

Commit Message

Jason Wang Sept. 24, 2019, 1:53 p.m.
Mdev bus only supports vfio driver right now, so it doesn't implement
match method. But in the future, we may add drivers other than vfio,
the first driver could be virtio-mdev. This means we need to add
device class id support in bus match method to pair the mdev device
and mdev driver correctly.

So this patch adds id_table to mdev_driver and class_id for mdev
parent with the match method for mdev bus.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 Documentation/driver-api/vfio-mediated-device.rst |  3 +++
 drivers/gpu/drm/i915/gvt/kvmgt.c                  |  1 +
 drivers/s390/cio/vfio_ccw_ops.c                   |  1 +
 drivers/s390/crypto/vfio_ap_ops.c                 |  1 +
 drivers/vfio/mdev/mdev_core.c                     |  7 +++++++
 drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
 drivers/vfio/mdev/mdev_private.h                  |  1 +
 drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
 include/linux/mdev.h                              |  8 ++++++++
 include/linux/mod_devicetable.h                   |  8 ++++++++
 samples/vfio-mdev/mbochs.c                        |  1 +
 samples/vfio-mdev/mdpy.c                          |  1 +
 samples/vfio-mdev/mtty.c                          |  1 +
 13 files changed, 53 insertions(+)

Patch hide | download patch | download mbox

diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
index 25eb7d5b834b..a5bdc60d62a1 100644
--- a/Documentation/driver-api/vfio-mediated-device.rst
+++ b/Documentation/driver-api/vfio-mediated-device.rst
@@ -102,12 +102,14 @@  structure to represent a mediated device's driver::
       * @probe: called when new device created
       * @remove: called when device removed
       * @driver: device driver structure
+      * @id_table: the ids serviced by this driver
       */
      struct mdev_driver {
 	     const char *name;
 	     int  (*probe)  (struct device *dev);
 	     void (*remove) (struct device *dev);
 	     struct device_driver    driver;
+	     const struct mdev_class_id *id_table;
      };
 
 A mediated bus driver for mdev should use this structure in the function calls
@@ -165,6 +167,7 @@  register itself with the mdev core driver::
 	extern int  mdev_register_device(struct device *dev,
 	                                 const struct mdev_parent_ops *ops);
 
+
 However, the mdev_parent_ops structure is not required in the function call
 that a driver should use to unregister itself with the mdev core driver::
 
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 23aa3e50cbf8..f793252a3d2a 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -678,6 +678,7 @@  static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
 		     dev_name(mdev_dev(mdev)));
 	ret = 0;
 
+	mdev_set_class_id(mdev, MDEV_ID_VFIO);
 out:
 	return ret;
 }
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index f0d71ab77c50..d258ef1fedb9 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -129,6 +129,7 @@  static int vfio_ccw_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
 			   private->sch->schid.ssid,
 			   private->sch->schid.sch_no);
 
+	mdev_set_class_id(mdev, MDEV_ID_VFIO);
 	return 0;
 }
 
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 5c0f53c6dde7..2cfd96112aa0 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -343,6 +343,7 @@  static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
 	list_add(&matrix_mdev->node, &matrix_dev->mdev_list);
 	mutex_unlock(&matrix_dev->lock);
 
+	mdev_set_class_id(mdev, MDEV_ID_VFIO);
 	return 0;
 }
 
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index b558d4cfd082..8764cf4a276d 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -45,6 +45,12 @@  void mdev_set_drvdata(struct mdev_device *mdev, void *data)
 }
 EXPORT_SYMBOL(mdev_set_drvdata);
 
+void mdev_set_class_id(struct mdev_device *mdev, u16 id)
+{
+	mdev->class_id = id;
+}
+EXPORT_SYMBOL(mdev_set_class_id);
+
 struct device *mdev_dev(struct mdev_device *mdev)
 {
 	return &mdev->dev;
@@ -135,6 +141,7 @@  static int mdev_device_remove_cb(struct device *dev, void *data)
  * mdev_register_device : Register a device
  * @dev: device structure representing parent device.
  * @ops: Parent device operation structure to be registered.
+ * @id: device id.
  *
  * Add device to list of registered parent devices.
  * Returns a negative value on error, otherwise 0.
diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
index 0d3223aee20b..b7c40ce86ee3 100644
--- a/drivers/vfio/mdev/mdev_driver.c
+++ b/drivers/vfio/mdev/mdev_driver.c
@@ -69,8 +69,22 @@  static int mdev_remove(struct device *dev)
 	return 0;
 }
 
+static int mdev_match(struct device *dev, struct device_driver *drv)
+{
+	unsigned int i;
+	struct mdev_device *mdev = to_mdev_device(dev);
+	struct mdev_driver *mdrv = to_mdev_driver(drv);
+	const struct mdev_class_id *ids = mdrv->id_table;
+
+	for (i = 0; ids[i].id; i++)
+		if (ids[i].id == mdev->class_id)
+			return 1;
+	return 0;
+}
+
 struct bus_type mdev_bus_type = {
 	.name		= "mdev",
+	.match		= mdev_match,
 	.probe		= mdev_probe,
 	.remove		= mdev_remove,
 };
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
index 7d922950caaf..c65f436c1869 100644
--- a/drivers/vfio/mdev/mdev_private.h
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -33,6 +33,7 @@  struct mdev_device {
 	struct kobject *type_kobj;
 	struct device *iommu_device;
 	bool active;
+	u16 class_id;
 };
 
 #define to_mdev_device(dev)	container_of(dev, struct mdev_device, dev)
diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
index 30964a4e0a28..fd2a4d9a3f26 100644
--- a/drivers/vfio/mdev/vfio_mdev.c
+++ b/drivers/vfio/mdev/vfio_mdev.c
@@ -120,10 +120,16 @@  static void vfio_mdev_remove(struct device *dev)
 	vfio_del_group_dev(dev);
 }
 
+static struct mdev_class_id id_table[] = {
+	{ MDEV_ID_VFIO },
+	{ 0 },
+};
+
 static struct mdev_driver vfio_mdev_driver = {
 	.name	= "vfio_mdev",
 	.probe	= vfio_mdev_probe,
 	.remove	= vfio_mdev_remove,
+	.id_table = id_table,
 };
 
 static int __init vfio_mdev_init(void)
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 0ce30ca78db0..3974650c074f 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -118,6 +118,7 @@  struct mdev_type_attribute mdev_type_attr_##_name =		\
  * @probe: called when new device created
  * @remove: called when device removed
  * @driver: device driver structure
+ * @id_table: the ids serviced by this driver.
  *
  **/
 struct mdev_driver {
@@ -125,12 +126,14 @@  struct mdev_driver {
 	int  (*probe)(struct device *dev);
 	void (*remove)(struct device *dev);
 	struct device_driver driver;
+	const struct mdev_class_id *id_table;
 };
 
 #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
 
 void *mdev_get_drvdata(struct mdev_device *mdev);
 void mdev_set_drvdata(struct mdev_device *mdev, void *data);
+void mdev_set_class_id(struct mdev_device *mdev, u16 id);
 const guid_t *mdev_uuid(struct mdev_device *mdev);
 
 extern struct bus_type mdev_bus_type;
@@ -145,4 +148,9 @@  struct device *mdev_parent_dev(struct mdev_device *mdev);
 struct device *mdev_dev(struct mdev_device *mdev);
 struct mdev_device *mdev_from_dev(struct device *dev);
 
+enum {
+	MDEV_ID_VFIO = 1,
+	/* New entries must be added here */
+};
+
 #endif /* MDEV_H */
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 5714fd35a83c..f32c6e44fb1a 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -821,4 +821,12 @@  struct wmi_device_id {
 	const void *context;
 };
 
+/**
+ * struct mdev_class_id - MDEV device class identifier
+ * @id: Used to identify a specific class of device, e.g vfio-mdev device.
+ */
+struct mdev_class_id {
+	__u16 id;
+};
+
 #endif /* LINUX_MOD_DEVICETABLE_H */
diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index ac5c8c17b1ff..8a8583c892b2 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -561,6 +561,7 @@  static int mbochs_create(struct kobject *kobj, struct mdev_device *mdev)
 	mbochs_reset(mdev);
 
 	mbochs_used_mbytes += type->mbytes;
+	mdev_set_class_id(mdev, MDEV_ID_VFIO);
 	return 0;
 
 err_mem:
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index cc86bf6566e4..88d7e76f3836 100644
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -269,6 +269,7 @@  static int mdpy_create(struct kobject *kobj, struct mdev_device *mdev)
 	mdpy_reset(mdev);
 
 	mdpy_count++;
+	mdev_set_class_id(mdev, MDEV_ID_VFIO);
 	return 0;
 }
 
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index 92e770a06ea2..4e0735143b69 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -770,6 +770,7 @@  static int mtty_create(struct kobject *kobj, struct mdev_device *mdev)
 	list_add(&mdev_state->next, &mdev_devices_list);
 	mutex_unlock(&mdev_list_lock);
 
+	mdev_set_class_id(mdev, MDEV_ID_VFIO);
 	return 0;
 }
 

Comments

On Tue, 24 Sep 2019 21:53:26 +0800
Jason Wang <jasowang@redhat.com> wrote:

> Mdev bus only supports vfio driver right now, so it doesn't implement
> match method. But in the future, we may add drivers other than vfio,
> the first driver could be virtio-mdev. This means we need to add
> device class id support in bus match method to pair the mdev device
> and mdev driver correctly.
> 
> So this patch adds id_table to mdev_driver and class_id for mdev
> parent with the match method for mdev bus.

Description needs to be revised from v1, class_id is no longer on the
parent.

> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  Documentation/driver-api/vfio-mediated-device.rst |  3 +++
>  drivers/gpu/drm/i915/gvt/kvmgt.c                  |  1 +
>  drivers/s390/cio/vfio_ccw_ops.c                   |  1 +
>  drivers/s390/crypto/vfio_ap_ops.c                 |  1 +
>  drivers/vfio/mdev/mdev_core.c                     |  7 +++++++
>  drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
>  drivers/vfio/mdev/mdev_private.h                  |  1 +
>  drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
>  include/linux/mdev.h                              |  8 ++++++++
>  include/linux/mod_devicetable.h                   |  8 ++++++++
>  samples/vfio-mdev/mbochs.c                        |  1 +
>  samples/vfio-mdev/mdpy.c                          |  1 +
>  samples/vfio-mdev/mtty.c                          |  1 +
>  13 files changed, 53 insertions(+)
> 
> diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
> index 25eb7d5b834b..a5bdc60d62a1 100644
> --- a/Documentation/driver-api/vfio-mediated-device.rst
> +++ b/Documentation/driver-api/vfio-mediated-device.rst
> @@ -102,12 +102,14 @@ structure to represent a mediated device's driver::
>        * @probe: called when new device created
>        * @remove: called when device removed
>        * @driver: device driver structure
> +      * @id_table: the ids serviced by this driver
>        */
>       struct mdev_driver {
>  	     const char *name;
>  	     int  (*probe)  (struct device *dev);
>  	     void (*remove) (struct device *dev);
>  	     struct device_driver    driver;
> +	     const struct mdev_class_id *id_table;
>       };
>  
>  A mediated bus driver for mdev should use this structure in the function calls
> @@ -165,6 +167,7 @@ register itself with the mdev core driver::
>  	extern int  mdev_register_device(struct device *dev,
>  	                                 const struct mdev_parent_ops *ops);
>  
> +
>  However, the mdev_parent_ops structure is not required in the function call
>  that a driver should use to unregister itself with the mdev core driver::

Unintended extra line?  Doesn't seem to match surrounding formatting.

Calling mdev_set_class_id() as part of create seems relatively
fundamental to the vendor driver with this change, it should be added
to the documentation.

> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 23aa3e50cbf8..f793252a3d2a 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -678,6 +678,7 @@ static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
>  		     dev_name(mdev_dev(mdev)));
>  	ret = 0;
>  
> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>  out:
>  	return ret;
>  }
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
> index f0d71ab77c50..d258ef1fedb9 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -129,6 +129,7 @@ static int vfio_ccw_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
>  			   private->sch->schid.ssid,
>  			   private->sch->schid.sch_no);
>  
> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>  	return 0;
>  }
>  
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 5c0f53c6dde7..2cfd96112aa0 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -343,6 +343,7 @@ static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
>  	list_add(&matrix_mdev->node, &matrix_dev->mdev_list);
>  	mutex_unlock(&matrix_dev->lock);
>  
> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>  	return 0;
>  }
>  
> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
> index b558d4cfd082..8764cf4a276d 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -45,6 +45,12 @@ void mdev_set_drvdata(struct mdev_device *mdev, void *data)
>  }
>  EXPORT_SYMBOL(mdev_set_drvdata);
>  
> +void mdev_set_class_id(struct mdev_device *mdev, u16 id)
> +{
> +	mdev->class_id = id;
> +}
> +EXPORT_SYMBOL(mdev_set_class_id);
> +
>  struct device *mdev_dev(struct mdev_device *mdev)
>  {
>  	return &mdev->dev;
> @@ -135,6 +141,7 @@ static int mdev_device_remove_cb(struct device *dev, void *data)
>   * mdev_register_device : Register a device
>   * @dev: device structure representing parent device.
>   * @ops: Parent device operation structure to be registered.
> + * @id: device id.
>   *
>   * Add device to list of registered parent devices.
>   * Returns a negative value on error, otherwise 0.
> diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
> index 0d3223aee20b..b7c40ce86ee3 100644
> --- a/drivers/vfio/mdev/mdev_driver.c
> +++ b/drivers/vfio/mdev/mdev_driver.c
> @@ -69,8 +69,22 @@ static int mdev_remove(struct device *dev)
>  	return 0;
>  }
>  
> +static int mdev_match(struct device *dev, struct device_driver *drv)
> +{
> +	unsigned int i;
> +	struct mdev_device *mdev = to_mdev_device(dev);
> +	struct mdev_driver *mdrv = to_mdev_driver(drv);
> +	const struct mdev_class_id *ids = mdrv->id_table;
> +
> +	for (i = 0; ids[i].id; i++)
> +		if (ids[i].id == mdev->class_id)

With the proposed API here, mdev->class_id can be NULL, do we allow
devices to exist in that state or should mdev_device_create() generate
an error if the .create() callback doesn't register a type?  Or a
warn_once and assume MDEV_ID_VFIO?  The latter seems pretty sketchy
when we get to patch 5/8.  Thanks,

Alex

> +			return 1;
> +	return 0;
> +}
> +
>  struct bus_type mdev_bus_type = {
>  	.name		= "mdev",
> +	.match		= mdev_match,
>  	.probe		= mdev_probe,
>  	.remove		= mdev_remove,
>  };
> diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
> index 7d922950caaf..c65f436c1869 100644
> --- a/drivers/vfio/mdev/mdev_private.h
> +++ b/drivers/vfio/mdev/mdev_private.h
> @@ -33,6 +33,7 @@ struct mdev_device {
>  	struct kobject *type_kobj;
>  	struct device *iommu_device;
>  	bool active;
> +	u16 class_id;
>  };
>  
>  #define to_mdev_device(dev)	container_of(dev, struct mdev_device, dev)
> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
> index 30964a4e0a28..fd2a4d9a3f26 100644
> --- a/drivers/vfio/mdev/vfio_mdev.c
> +++ b/drivers/vfio/mdev/vfio_mdev.c
> @@ -120,10 +120,16 @@ static void vfio_mdev_remove(struct device *dev)
>  	vfio_del_group_dev(dev);
>  }
>  
> +static struct mdev_class_id id_table[] = {
> +	{ MDEV_ID_VFIO },
> +	{ 0 },
> +};
> +
>  static struct mdev_driver vfio_mdev_driver = {
>  	.name	= "vfio_mdev",
>  	.probe	= vfio_mdev_probe,
>  	.remove	= vfio_mdev_remove,
> +	.id_table = id_table,
>  };
>  
>  static int __init vfio_mdev_init(void)
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index 0ce30ca78db0..3974650c074f 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -118,6 +118,7 @@ struct mdev_type_attribute mdev_type_attr_##_name =		\
>   * @probe: called when new device created
>   * @remove: called when device removed
>   * @driver: device driver structure
> + * @id_table: the ids serviced by this driver.
>   *
>   **/
>  struct mdev_driver {
> @@ -125,12 +126,14 @@ struct mdev_driver {
>  	int  (*probe)(struct device *dev);
>  	void (*remove)(struct device *dev);
>  	struct device_driver driver;
> +	const struct mdev_class_id *id_table;
>  };
>  
>  #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
>  
>  void *mdev_get_drvdata(struct mdev_device *mdev);
>  void mdev_set_drvdata(struct mdev_device *mdev, void *data);
> +void mdev_set_class_id(struct mdev_device *mdev, u16 id);
>  const guid_t *mdev_uuid(struct mdev_device *mdev);
>  
>  extern struct bus_type mdev_bus_type;
> @@ -145,4 +148,9 @@ struct device *mdev_parent_dev(struct mdev_device *mdev);
>  struct device *mdev_dev(struct mdev_device *mdev);
>  struct mdev_device *mdev_from_dev(struct device *dev);
>  
> +enum {
> +	MDEV_ID_VFIO = 1,
> +	/* New entries must be added here */
> +};
> +
>  #endif /* MDEV_H */
> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> index 5714fd35a83c..f32c6e44fb1a 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -821,4 +821,12 @@ struct wmi_device_id {
>  	const void *context;
>  };
>  
> +/**
> + * struct mdev_class_id - MDEV device class identifier
> + * @id: Used to identify a specific class of device, e.g vfio-mdev device.
> + */
> +struct mdev_class_id {
> +	__u16 id;
> +};
> +
>  #endif /* LINUX_MOD_DEVICETABLE_H */
> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
> index ac5c8c17b1ff..8a8583c892b2 100644
> --- a/samples/vfio-mdev/mbochs.c
> +++ b/samples/vfio-mdev/mbochs.c
> @@ -561,6 +561,7 @@ static int mbochs_create(struct kobject *kobj, struct mdev_device *mdev)
>  	mbochs_reset(mdev);
>  
>  	mbochs_used_mbytes += type->mbytes;
> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>  	return 0;
>  
>  err_mem:
> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
> index cc86bf6566e4..88d7e76f3836 100644
> --- a/samples/vfio-mdev/mdpy.c
> +++ b/samples/vfio-mdev/mdpy.c
> @@ -269,6 +269,7 @@ static int mdpy_create(struct kobject *kobj, struct mdev_device *mdev)
>  	mdpy_reset(mdev);
>  
>  	mdpy_count++;
> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>  	return 0;
>  }
>  
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
> index 92e770a06ea2..4e0735143b69 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -770,6 +770,7 @@ static int mtty_create(struct kobject *kobj, struct mdev_device *mdev)
>  	list_add(&mdev_state->next, &mdev_devices_list);
>  	mutex_unlock(&mdev_list_lock);
>  
> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>  	return 0;
>  }
>
> From: Jason Wang
> Sent: Tuesday, September 24, 2019 9:53 PM
> 
> Mdev bus only supports vfio driver right now, so it doesn't implement
> match method. But in the future, we may add drivers other than vfio,
> the first driver could be virtio-mdev. This means we need to add
> device class id support in bus match method to pair the mdev device
> and mdev driver correctly.
> 
> So this patch adds id_table to mdev_driver and class_id for mdev
> parent with the match method for mdev bus.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  Documentation/driver-api/vfio-mediated-device.rst |  3 +++
>  drivers/gpu/drm/i915/gvt/kvmgt.c                  |  1 +
>  drivers/s390/cio/vfio_ccw_ops.c                   |  1 +
>  drivers/s390/crypto/vfio_ap_ops.c                 |  1 +
>  drivers/vfio/mdev/mdev_core.c                     |  7 +++++++
>  drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
>  drivers/vfio/mdev/mdev_private.h                  |  1 +
>  drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
>  include/linux/mdev.h                              |  8 ++++++++
>  include/linux/mod_devicetable.h                   |  8 ++++++++
>  samples/vfio-mdev/mbochs.c                        |  1 +
>  samples/vfio-mdev/mdpy.c                          |  1 +
>  samples/vfio-mdev/mtty.c                          |  1 +
>  13 files changed, 53 insertions(+)
> 
> diff --git a/Documentation/driver-api/vfio-mediated-device.rst
> b/Documentation/driver-api/vfio-mediated-device.rst
> index 25eb7d5b834b..a5bdc60d62a1 100644
> --- a/Documentation/driver-api/vfio-mediated-device.rst
> +++ b/Documentation/driver-api/vfio-mediated-device.rst
> @@ -102,12 +102,14 @@ structure to represent a mediated device's
> driver::
>        * @probe: called when new device created
>        * @remove: called when device removed
>        * @driver: device driver structure
> +      * @id_table: the ids serviced by this driver
>        */
>       struct mdev_driver {
>  	     const char *name;
>  	     int  (*probe)  (struct device *dev);
>  	     void (*remove) (struct device *dev);
>  	     struct device_driver    driver;
> +	     const struct mdev_class_id *id_table;
>       };
> 
>  A mediated bus driver for mdev should use this structure in the function
> calls
> @@ -165,6 +167,7 @@ register itself with the mdev core driver::
>  	extern int  mdev_register_device(struct device *dev,
>  	                                 const struct mdev_parent_ops *ops);
> 
> +
>  However, the mdev_parent_ops structure is not required in the function
> call
>  that a driver should use to unregister itself with the mdev core driver::
> 
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c
> b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 23aa3e50cbf8..f793252a3d2a 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -678,6 +678,7 @@ static int intel_vgpu_create(struct kobject *kobj,
> struct mdev_device *mdev)
>  		     dev_name(mdev_dev(mdev)));
>  	ret = 0;
> 
> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>  out:
>  	return ret;
>  }
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c
> b/drivers/s390/cio/vfio_ccw_ops.c
> index f0d71ab77c50..d258ef1fedb9 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -129,6 +129,7 @@ static int vfio_ccw_mdev_create(struct kobject
> *kobj, struct mdev_device *mdev)
>  			   private->sch->schid.ssid,
>  			   private->sch->schid.sch_no);
> 
> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>  	return 0;
>  }
> 
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c
> b/drivers/s390/crypto/vfio_ap_ops.c
> index 5c0f53c6dde7..2cfd96112aa0 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -343,6 +343,7 @@ static int vfio_ap_mdev_create(struct kobject *kobj,
> struct mdev_device *mdev)
>  	list_add(&matrix_mdev->node, &matrix_dev->mdev_list);
>  	mutex_unlock(&matrix_dev->lock);
> 
> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>  	return 0;
>  }
> 
> diff --git a/drivers/vfio/mdev/mdev_core.c
> b/drivers/vfio/mdev/mdev_core.c
> index b558d4cfd082..8764cf4a276d 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -45,6 +45,12 @@ void mdev_set_drvdata(struct mdev_device *mdev,
> void *data)
>  }
>  EXPORT_SYMBOL(mdev_set_drvdata);
> 
> +void mdev_set_class_id(struct mdev_device *mdev, u16 id)
> +{
> +	mdev->class_id = id;
> +}
> +EXPORT_SYMBOL(mdev_set_class_id);
> +
>  struct device *mdev_dev(struct mdev_device *mdev)
>  {
>  	return &mdev->dev;
> @@ -135,6 +141,7 @@ static int mdev_device_remove_cb(struct device
> *dev, void *data)
>   * mdev_register_device : Register a device
>   * @dev: device structure representing parent device.
>   * @ops: Parent device operation structure to be registered.
> + * @id: device id.

class id.

>   *
>   * Add device to list of registered parent devices.
>   * Returns a negative value on error, otherwise 0.
> diff --git a/drivers/vfio/mdev/mdev_driver.c
> b/drivers/vfio/mdev/mdev_driver.c
> index 0d3223aee20b..b7c40ce86ee3 100644
> --- a/drivers/vfio/mdev/mdev_driver.c
> +++ b/drivers/vfio/mdev/mdev_driver.c
> @@ -69,8 +69,22 @@ static int mdev_remove(struct device *dev)
>  	return 0;
>  }
> 
> +static int mdev_match(struct device *dev, struct device_driver *drv)
> +{
> +	unsigned int i;
> +	struct mdev_device *mdev = to_mdev_device(dev);
> +	struct mdev_driver *mdrv = to_mdev_driver(drv);
> +	const struct mdev_class_id *ids = mdrv->id_table;
> +
> +	for (i = 0; ids[i].id; i++)
> +		if (ids[i].id == mdev->class_id)
> +			return 1;
> +	return 0;
> +}
> +
>  struct bus_type mdev_bus_type = {
>  	.name		= "mdev",
> +	.match		= mdev_match,
>  	.probe		= mdev_probe,
>  	.remove		= mdev_remove,
>  };
> diff --git a/drivers/vfio/mdev/mdev_private.h
> b/drivers/vfio/mdev/mdev_private.h
> index 7d922950caaf..c65f436c1869 100644
> --- a/drivers/vfio/mdev/mdev_private.h
> +++ b/drivers/vfio/mdev/mdev_private.h
> @@ -33,6 +33,7 @@ struct mdev_device {
>  	struct kobject *type_kobj;
>  	struct device *iommu_device;
>  	bool active;
> +	u16 class_id;
>  };
> 
>  #define to_mdev_device(dev)	container_of(dev, struct mdev_device, dev)
> diff --git a/drivers/vfio/mdev/vfio_mdev.c
> b/drivers/vfio/mdev/vfio_mdev.c
> index 30964a4e0a28..fd2a4d9a3f26 100644
> --- a/drivers/vfio/mdev/vfio_mdev.c
> +++ b/drivers/vfio/mdev/vfio_mdev.c
> @@ -120,10 +120,16 @@ static void vfio_mdev_remove(struct device *dev)
>  	vfio_del_group_dev(dev);
>  }
> 
> +static struct mdev_class_id id_table[] = {
> +	{ MDEV_ID_VFIO },
> +	{ 0 },
> +};
> +
>  static struct mdev_driver vfio_mdev_driver = {
>  	.name	= "vfio_mdev",
>  	.probe	= vfio_mdev_probe,
>  	.remove	= vfio_mdev_remove,
> +	.id_table = id_table,
>  };
> 
>  static int __init vfio_mdev_init(void)
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index 0ce30ca78db0..3974650c074f 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -118,6 +118,7 @@ struct mdev_type_attribute
> mdev_type_attr_##_name =		\
>   * @probe: called when new device created
>   * @remove: called when device removed
>   * @driver: device driver structure
> + * @id_table: the ids serviced by this driver.
>   *
>   **/
>  struct mdev_driver {
> @@ -125,12 +126,14 @@ struct mdev_driver {
>  	int  (*probe)(struct device *dev);
>  	void (*remove)(struct device *dev);
>  	struct device_driver driver;
> +	const struct mdev_class_id *id_table;
>  };
> 
>  #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
> 
>  void *mdev_get_drvdata(struct mdev_device *mdev);
>  void mdev_set_drvdata(struct mdev_device *mdev, void *data);
> +void mdev_set_class_id(struct mdev_device *mdev, u16 id);
>  const guid_t *mdev_uuid(struct mdev_device *mdev);
> 
>  extern struct bus_type mdev_bus_type;
> @@ -145,4 +148,9 @@ struct device *mdev_parent_dev(struct
> mdev_device *mdev);
>  struct device *mdev_dev(struct mdev_device *mdev);
>  struct mdev_device *mdev_from_dev(struct device *dev);
> 
> +enum {
> +	MDEV_ID_VFIO = 1,
> +	/* New entries must be added here */
> +};
> +
>  #endif /* MDEV_H */
> diff --git a/include/linux/mod_devicetable.h
> b/include/linux/mod_devicetable.h
> index 5714fd35a83c..f32c6e44fb1a 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -821,4 +821,12 @@ struct wmi_device_id {
>  	const void *context;
>  };
> 
> +/**
> + * struct mdev_class_id - MDEV device class identifier
> + * @id: Used to identify a specific class of device, e.g vfio-mdev device.
> + */
> +struct mdev_class_id {
> +	__u16 id;
> +};
> +
>  #endif /* LINUX_MOD_DEVICETABLE_H */
> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
> index ac5c8c17b1ff..8a8583c892b2 100644
> --- a/samples/vfio-mdev/mbochs.c
> +++ b/samples/vfio-mdev/mbochs.c
> @@ -561,6 +561,7 @@ static int mbochs_create(struct kobject *kobj, struct
> mdev_device *mdev)
>  	mbochs_reset(mdev);
> 
>  	mbochs_used_mbytes += type->mbytes;
> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>  	return 0;
> 
>  err_mem:
> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
> index cc86bf6566e4..88d7e76f3836 100644
> --- a/samples/vfio-mdev/mdpy.c
> +++ b/samples/vfio-mdev/mdpy.c
> @@ -269,6 +269,7 @@ static int mdpy_create(struct kobject *kobj, struct
> mdev_device *mdev)
>  	mdpy_reset(mdev);
> 
>  	mdpy_count++;
> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>  	return 0;
>  }
> 
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
> index 92e770a06ea2..4e0735143b69 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -770,6 +770,7 @@ static int mtty_create(struct kobject *kobj, struct
> mdev_device *mdev)
>  	list_add(&mdev_state->next, &mdev_devices_list);
>  	mutex_unlock(&mdev_list_lock);
> 
> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>  	return 0;
>  }
> 
> --
> 2.19.1
On 2019/9/25 上午7:06, Alex Williamson wrote:
> On Tue, 24 Sep 2019 21:53:26 +0800
> Jason Wang <jasowang@redhat.com> wrote:
>
>> Mdev bus only supports vfio driver right now, so it doesn't implement
>> match method. But in the future, we may add drivers other than vfio,
>> the first driver could be virtio-mdev. This means we need to add
>> device class id support in bus match method to pair the mdev device
>> and mdev driver correctly.
>>
>> So this patch adds id_table to mdev_driver and class_id for mdev
>> parent with the match method for mdev bus.
> Description needs to be revised from v1, class_id is no longer on the
> parent.


Yes, will fix.


>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>  Documentation/driver-api/vfio-mediated-device.rst |  3 +++
>>  drivers/gpu/drm/i915/gvt/kvmgt.c                  |  1 +
>>  drivers/s390/cio/vfio_ccw_ops.c                   |  1 +
>>  drivers/s390/crypto/vfio_ap_ops.c                 |  1 +
>>  drivers/vfio/mdev/mdev_core.c                     |  7 +++++++
>>  drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
>>  drivers/vfio/mdev/mdev_private.h                  |  1 +
>>  drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
>>  include/linux/mdev.h                              |  8 ++++++++
>>  include/linux/mod_devicetable.h                   |  8 ++++++++
>>  samples/vfio-mdev/mbochs.c                        |  1 +
>>  samples/vfio-mdev/mdpy.c                          |  1 +
>>  samples/vfio-mdev/mtty.c                          |  1 +
>>  13 files changed, 53 insertions(+)
>>
>> diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
>> index 25eb7d5b834b..a5bdc60d62a1 100644
>> --- a/Documentation/driver-api/vfio-mediated-device.rst
>> +++ b/Documentation/driver-api/vfio-mediated-device.rst
>> @@ -102,12 +102,14 @@ structure to represent a mediated device's driver::
>>        * @probe: called when new device created
>>        * @remove: called when device removed
>>        * @driver: device driver structure
>> +      * @id_table: the ids serviced by this driver
>>        */
>>       struct mdev_driver {
>>  	     const char *name;
>>  	     int  (*probe)  (struct device *dev);
>>  	     void (*remove) (struct device *dev);
>>  	     struct device_driver    driver;
>> +	     const struct mdev_class_id *id_table;
>>       };
>>  
>>  A mediated bus driver for mdev should use this structure in the function calls
>> @@ -165,6 +167,7 @@ register itself with the mdev core driver::
>>  	extern int  mdev_register_device(struct device *dev,
>>  	                                 const struct mdev_parent_ops *ops);
>>  
>> +
>>  However, the mdev_parent_ops structure is not required in the function call
>>  that a driver should use to unregister itself with the mdev core driver::
> Unintended extra line?  Doesn't seem to match surrounding formatting.
>
> Calling mdev_set_class_id() as part of create seems relatively
> fundamental to the vendor driver with this change, it should be added
> to the documentation.


Right.


>
>> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
>> index 23aa3e50cbf8..f793252a3d2a 100644
>> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
>> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
>> @@ -678,6 +678,7 @@ static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
>>  		     dev_name(mdev_dev(mdev)));
>>  	ret = 0;
>>  
>> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>>  out:
>>  	return ret;
>>  }
>> diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
>> index f0d71ab77c50..d258ef1fedb9 100644
>> --- a/drivers/s390/cio/vfio_ccw_ops.c
>> +++ b/drivers/s390/cio/vfio_ccw_ops.c
>> @@ -129,6 +129,7 @@ static int vfio_ccw_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
>>  			   private->sch->schid.ssid,
>>  			   private->sch->schid.sch_no);
>>  
>> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>>  	return 0;
>>  }
>>  
>> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
>> index 5c0f53c6dde7..2cfd96112aa0 100644
>> --- a/drivers/s390/crypto/vfio_ap_ops.c
>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
>> @@ -343,6 +343,7 @@ static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
>>  	list_add(&matrix_mdev->node, &matrix_dev->mdev_list);
>>  	mutex_unlock(&matrix_dev->lock);
>>  
>> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>>  	return 0;
>>  }
>>  
>> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
>> index b558d4cfd082..8764cf4a276d 100644
>> --- a/drivers/vfio/mdev/mdev_core.c
>> +++ b/drivers/vfio/mdev/mdev_core.c
>> @@ -45,6 +45,12 @@ void mdev_set_drvdata(struct mdev_device *mdev, void *data)
>>  }
>>  EXPORT_SYMBOL(mdev_set_drvdata);
>>  
>> +void mdev_set_class_id(struct mdev_device *mdev, u16 id)
>> +{
>> +	mdev->class_id = id;
>> +}
>> +EXPORT_SYMBOL(mdev_set_class_id);
>> +
>>  struct device *mdev_dev(struct mdev_device *mdev)
>>  {
>>  	return &mdev->dev;
>> @@ -135,6 +141,7 @@ static int mdev_device_remove_cb(struct device *dev, void *data)
>>   * mdev_register_device : Register a device
>>   * @dev: device structure representing parent device.
>>   * @ops: Parent device operation structure to be registered.
>> + * @id: device id.
>>   *
>>   * Add device to list of registered parent devices.
>>   * Returns a negative value on error, otherwise 0.
>> diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
>> index 0d3223aee20b..b7c40ce86ee3 100644
>> --- a/drivers/vfio/mdev/mdev_driver.c
>> +++ b/drivers/vfio/mdev/mdev_driver.c
>> @@ -69,8 +69,22 @@ static int mdev_remove(struct device *dev)
>>  	return 0;
>>  }
>>  
>> +static int mdev_match(struct device *dev, struct device_driver *drv)
>> +{
>> +	unsigned int i;
>> +	struct mdev_device *mdev = to_mdev_device(dev);
>> +	struct mdev_driver *mdrv = to_mdev_driver(drv);
>> +	const struct mdev_class_id *ids = mdrv->id_table;
>> +
>> +	for (i = 0; ids[i].id; i++)
>> +		if (ids[i].id == mdev->class_id)
> With the proposed API here, mdev->class_id can be NULL, do we allow
> devices to exist in that state or should mdev_device_create() generate
> an error if the .create() callback doesn't register a type?  Or a
> warn_once and assume MDEV_ID_VFIO?  The latter seems pretty sketchy
> when we get to patch 5/8.  Thanks,


It looks to me the error from mdev_device_create() is better.

Thanks


>
> Alex
>
>> +			return 1;
>> +	return 0;
>> +}
>> +
>>  struct bus_type mdev_bus_type = {
>>  	.name		= "mdev",
>> +	.match		= mdev_match,
>>  	.probe		= mdev_probe,
>>  	.remove		= mdev_remove,
>>  };
>> diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
>> index 7d922950caaf..c65f436c1869 100644
>> --- a/drivers/vfio/mdev/mdev_private.h
>> +++ b/drivers/vfio/mdev/mdev_private.h
>> @@ -33,6 +33,7 @@ struct mdev_device {
>>  	struct kobject *type_kobj;
>>  	struct device *iommu_device;
>>  	bool active;
>> +	u16 class_id;
>>  };
>>  
>>  #define to_mdev_device(dev)	container_of(dev, struct mdev_device, dev)
>> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
>> index 30964a4e0a28..fd2a4d9a3f26 100644
>> --- a/drivers/vfio/mdev/vfio_mdev.c
>> +++ b/drivers/vfio/mdev/vfio_mdev.c
>> @@ -120,10 +120,16 @@ static void vfio_mdev_remove(struct device *dev)
>>  	vfio_del_group_dev(dev);
>>  }
>>  
>> +static struct mdev_class_id id_table[] = {
>> +	{ MDEV_ID_VFIO },
>> +	{ 0 },
>> +};
>> +
>>  static struct mdev_driver vfio_mdev_driver = {
>>  	.name	= "vfio_mdev",
>>  	.probe	= vfio_mdev_probe,
>>  	.remove	= vfio_mdev_remove,
>> +	.id_table = id_table,
>>  };
>>  
>>  static int __init vfio_mdev_init(void)
>> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
>> index 0ce30ca78db0..3974650c074f 100644
>> --- a/include/linux/mdev.h
>> +++ b/include/linux/mdev.h
>> @@ -118,6 +118,7 @@ struct mdev_type_attribute mdev_type_attr_##_name =		\
>>   * @probe: called when new device created
>>   * @remove: called when device removed
>>   * @driver: device driver structure
>> + * @id_table: the ids serviced by this driver.
>>   *
>>   **/
>>  struct mdev_driver {
>> @@ -125,12 +126,14 @@ struct mdev_driver {
>>  	int  (*probe)(struct device *dev);
>>  	void (*remove)(struct device *dev);
>>  	struct device_driver driver;
>> +	const struct mdev_class_id *id_table;
>>  };
>>  
>>  #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
>>  
>>  void *mdev_get_drvdata(struct mdev_device *mdev);
>>  void mdev_set_drvdata(struct mdev_device *mdev, void *data);
>> +void mdev_set_class_id(struct mdev_device *mdev, u16 id);
>>  const guid_t *mdev_uuid(struct mdev_device *mdev);
>>  
>>  extern struct bus_type mdev_bus_type;
>> @@ -145,4 +148,9 @@ struct device *mdev_parent_dev(struct mdev_device *mdev);
>>  struct device *mdev_dev(struct mdev_device *mdev);
>>  struct mdev_device *mdev_from_dev(struct device *dev);
>>  
>> +enum {
>> +	MDEV_ID_VFIO = 1,
>> +	/* New entries must be added here */
>> +};
>> +
>>  #endif /* MDEV_H */
>> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
>> index 5714fd35a83c..f32c6e44fb1a 100644
>> --- a/include/linux/mod_devicetable.h
>> +++ b/include/linux/mod_devicetable.h
>> @@ -821,4 +821,12 @@ struct wmi_device_id {
>>  	const void *context;
>>  };
>>  
>> +/**
>> + * struct mdev_class_id - MDEV device class identifier
>> + * @id: Used to identify a specific class of device, e.g vfio-mdev device.
>> + */
>> +struct mdev_class_id {
>> +	__u16 id;
>> +};
>> +
>>  #endif /* LINUX_MOD_DEVICETABLE_H */
>> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
>> index ac5c8c17b1ff..8a8583c892b2 100644
>> --- a/samples/vfio-mdev/mbochs.c
>> +++ b/samples/vfio-mdev/mbochs.c
>> @@ -561,6 +561,7 @@ static int mbochs_create(struct kobject *kobj, struct mdev_device *mdev)
>>  	mbochs_reset(mdev);
>>  
>>  	mbochs_used_mbytes += type->mbytes;
>> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>>  	return 0;
>>  
>>  err_mem:
>> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
>> index cc86bf6566e4..88d7e76f3836 100644
>> --- a/samples/vfio-mdev/mdpy.c
>> +++ b/samples/vfio-mdev/mdpy.c
>> @@ -269,6 +269,7 @@ static int mdpy_create(struct kobject *kobj, struct mdev_device *mdev)
>>  	mdpy_reset(mdev);
>>  
>>  	mdpy_count++;
>> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>>  	return 0;
>>  }
>>  
>> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
>> index 92e770a06ea2..4e0735143b69 100644
>> --- a/samples/vfio-mdev/mtty.c
>> +++ b/samples/vfio-mdev/mtty.c
>> @@ -770,6 +770,7 @@ static int mtty_create(struct kobject *kobj, struct mdev_device *mdev)
>>  	list_add(&mdev_state->next, &mdev_devices_list);
>>  	mutex_unlock(&mdev_list_lock);
>>  
>> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>>  	return 0;
>>  }
>>
On 2019/9/25 下午4:28, Tian, Kevin wrote:
>> From: Jason Wang
>> Sent: Tuesday, September 24, 2019 9:53 PM
>>
>> Mdev bus only supports vfio driver right now, so it doesn't implement
>> match method. But in the future, we may add drivers other than vfio,
>> the first driver could be virtio-mdev. This means we need to add
>> device class id support in bus match method to pair the mdev device
>> and mdev driver correctly.
>>
>> So this patch adds id_table to mdev_driver and class_id for mdev
>> parent with the match method for mdev bus.
>>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>  Documentation/driver-api/vfio-mediated-device.rst |  3 +++
>>  drivers/gpu/drm/i915/gvt/kvmgt.c                  |  1 +
>>  drivers/s390/cio/vfio_ccw_ops.c                   |  1 +
>>  drivers/s390/crypto/vfio_ap_ops.c                 |  1 +
>>  drivers/vfio/mdev/mdev_core.c                     |  7 +++++++
>>  drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
>>  drivers/vfio/mdev/mdev_private.h                  |  1 +
>>  drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
>>  include/linux/mdev.h                              |  8 ++++++++
>>  include/linux/mod_devicetable.h                   |  8 ++++++++
>>  samples/vfio-mdev/mbochs.c                        |  1 +
>>  samples/vfio-mdev/mdpy.c                          |  1 +
>>  samples/vfio-mdev/mtty.c                          |  1 +
>>  13 files changed, 53 insertions(+)
>>
>> diff --git a/Documentation/driver-api/vfio-mediated-device.rst
>> b/Documentation/driver-api/vfio-mediated-device.rst
>> index 25eb7d5b834b..a5bdc60d62a1 100644
>> --- a/Documentation/driver-api/vfio-mediated-device.rst
>> +++ b/Documentation/driver-api/vfio-mediated-device.rst
>> @@ -102,12 +102,14 @@ structure to represent a mediated device's
>> driver::
>>        * @probe: called when new device created
>>        * @remove: called when device removed
>>        * @driver: device driver structure
>> +      * @id_table: the ids serviced by this driver
>>        */
>>       struct mdev_driver {
>>  	     const char *name;
>>  	     int  (*probe)  (struct device *dev);
>>  	     void (*remove) (struct device *dev);
>>  	     struct device_driver    driver;
>> +	     const struct mdev_class_id *id_table;
>>       };
>>
>>  A mediated bus driver for mdev should use this structure in the function
>> calls
>> @@ -165,6 +167,7 @@ register itself with the mdev core driver::
>>  	extern int  mdev_register_device(struct device *dev,
>>  	                                 const struct mdev_parent_ops *ops);
>>
>> +
>>  However, the mdev_parent_ops structure is not required in the function
>> call
>>  that a driver should use to unregister itself with the mdev core driver::
>>
>> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c
>> b/drivers/gpu/drm/i915/gvt/kvmgt.c
>> index 23aa3e50cbf8..f793252a3d2a 100644
>> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
>> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
>> @@ -678,6 +678,7 @@ static int intel_vgpu_create(struct kobject *kobj,
>> struct mdev_device *mdev)
>>  		     dev_name(mdev_dev(mdev)));
>>  	ret = 0;
>>
>> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>>  out:
>>  	return ret;
>>  }
>> diff --git a/drivers/s390/cio/vfio_ccw_ops.c
>> b/drivers/s390/cio/vfio_ccw_ops.c
>> index f0d71ab77c50..d258ef1fedb9 100644
>> --- a/drivers/s390/cio/vfio_ccw_ops.c
>> +++ b/drivers/s390/cio/vfio_ccw_ops.c
>> @@ -129,6 +129,7 @@ static int vfio_ccw_mdev_create(struct kobject
>> *kobj, struct mdev_device *mdev)
>>  			   private->sch->schid.ssid,
>>  			   private->sch->schid.sch_no);
>>
>> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>>  	return 0;
>>  }
>>
>> diff --git a/drivers/s390/crypto/vfio_ap_ops.c
>> b/drivers/s390/crypto/vfio_ap_ops.c
>> index 5c0f53c6dde7..2cfd96112aa0 100644
>> --- a/drivers/s390/crypto/vfio_ap_ops.c
>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
>> @@ -343,6 +343,7 @@ static int vfio_ap_mdev_create(struct kobject *kobj,
>> struct mdev_device *mdev)
>>  	list_add(&matrix_mdev->node, &matrix_dev->mdev_list);
>>  	mutex_unlock(&matrix_dev->lock);
>>
>> +	mdev_set_class_id(mdev, MDEV_ID_VFIO);
>>  	return 0;
>>  }
>>
>> diff --git a/drivers/vfio/mdev/mdev_core.c
>> b/drivers/vfio/mdev/mdev_core.c
>> index b558d4cfd082..8764cf4a276d 100644
>> --- a/drivers/vfio/mdev/mdev_core.c
>> +++ b/drivers/vfio/mdev/mdev_core.c
>> @@ -45,6 +45,12 @@ void mdev_set_drvdata(struct mdev_device *mdev,
>> void *data)
>>  }
>>  EXPORT_SYMBOL(mdev_set_drvdata);
>>
>> +void mdev_set_class_id(struct mdev_device *mdev, u16 id)
>> +{
>> +	mdev->class_id = id;
>> +}
>> +EXPORT_SYMBOL(mdev_set_class_id);
>> +
>>  struct device *mdev_dev(struct mdev_device *mdev)
>>  {
>>  	return &mdev->dev;
>> @@ -135,6 +141,7 @@ static int mdev_device_remove_cb(struct device
>> *dev, void *data)
>>   * mdev_register_device : Register a device
>>   * @dev: device structure representing parent device.
>>   * @ops: Parent device operation structure to be registered.
>> + * @id: device id.
> class id.


Right, will fix.

Thanks